How Exceptional Was the 2015–2019 Central American Drought?

Abstract

The Central American Dry Corridor experienced five consecutive years of drought from 2015 to 2019. Here, we find that the severity of this drought was driven primarily by rainfall deficits in July–August. To determine if the magnitude of this event was outside the range of natural variability, we apply a statistical resampling method to observations that emulates internal climate variability. Our analyses show that droughts similar to the 2015–2019 event are possible, although extremely rare, even without anthropogenic influences. Persistent droughts in our ensemble are consistently linked to stronger easterly winds associated with the Caribbean Low‐Level Jet. We also examine the effects of temperature on soil moisture during this drought using the Palmer Drought Severity Index and show that anthropogenic warming increases the likelihood of severe deficits. Multi‐year droughts are likely to worsen by the end of the 21st century due to the compound effects of anthropogenic climate change.

Historical meteorological droughts over the CORDEX‐CAM (Central America, Caribbean and Mexico) domain: Evaluating the simulation of dry hot spots with RegCM4

“…'Dry hot spots' have been already identified over the western United States-Mexico border region (Stahle et al, 2009) and the Central American Dry Corridor (Anderson et al, 2023;Gotlieb et al, 2019;Quesada-Hern andez et al, 2019) on the Pacific side of northern Central America. Both regions experienced historical nonsignificant negative precipitation trends, and significant warming in recent decades (Cavazos et al, 2020;Hidalgo et al, 2019).…”

“…Also, during 2006-2011, droughts affected most of Mexico, reporting the largest number of affected populations in 2011 (2.5 million people) (S anchez-Rodríguez & Cavazos, 2015). Smaller extent droughts are also documented for southeast Mexico in the mid-summer drought (MSD) region and the Central America Dry Corridor on the Pacific side; this corridor is well known as a 'dry hot spot' (Anderson et al, 2023;Depsky & Pons, 2020;Gotlieb et al, 2019;Pascale et al, 2021;Quesada-Hern andez et al, 2019;Stewart et al, 2022). Some relevant droughts in this region occurred in 1985 and 2001 (Depsky & Pons, 2020) and in the Yucatan Peninsula in 1985-1987 and 1994 (M ardero et al, 2012).…”

“…Several studies based on precipitation and temperature have shown that most of the CAM has become warmer and drier during the last decades; weak drying conditions have been observed over the southwest United States and northwestern Mexico (Cavazos et al, 2020), with significant negative trends of accumulated precipitation over part of Sonora and Baja California (Colorado-Ruiz & Cavazos, 2021). Except for Honduras and northern Panama (Hidalgo et al, 2017), hydroclimatic trends over the CAM domain have shown warming of 0.3 C/decade during the late 20th and early 21st centuries (Cavazos et al, 2020;Hidalgo et al, 2017Hidalgo et al, , 2019, with inconsistent changes in precipitation and drought trends dependent on the data sets used over Central America and the Caribbean (Anderson et al, 2023;Hidalgo et al, 2017Hidalgo et al, , 2019Stewart et al, 2022).…”

Recent trends in agriculturally relevant climate in Central America

“…Over the preceding decade, the CADC has been afflicted by the most severe droughts witnessed in decades, resulting in disruption for over 1.3 million subsistence agriculturists and labourers, predominantly comprising marginalized Indigenous populations, causing substantial livelihood losses, marked instances of acute food insecurity, and prompting adjustments in their migratory behaviours (Anderson et al, 2023;Linke et al, 2023;Pons, 2021;Stringer et al, 2021). The primary migrant-sending countries of Central America and the CADC to the US/Mexico border are Guatemala, Honduras, and El Salvador (Angelo, 2021;Young, 2021).…”